Design concepts of a scaled-down autothermal membrane reformer for on board hydrogen production

Michael Patrascu; Moshe Sheintuch

doi:10.1016/j.cej.2015.02.031

Design concepts of a scaled-down autothermal membrane reformer for on board hydrogen production

Michael Patrascu^*, Moshe Sheintuch

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

Abstract

The design of an on-board autothermal membrane reactor producing pure hydrogen at atmospheric pressure, while recuperating heat, is analyzed mathematically. The suggested design incorporates two reactors exchanging heat; an endothermic methane steam-reforming (MSR) reactor embedding Pd membranes to separate pure H₂, and an exothermic methane oxidation (MOx) reactor fed by the MSR effluent. The analysis is conducted at three levels of details: (i) Thermodynamics reveals that the minimum operating temperature for high thermal efficiency under adiabatic conditions with full recycle of MSR effluents is 550 °C. Feeding the oxidation reactor with added fuel does not improve efficiency. (ii) A kinetic model that accounts for the permeance of the Pd membranes suggests even higher temperatures should be considered when operating with limited membrane area. The effect of catalytic kinetics is small. (iii) A transient detailed one-dimensional model considering heat exchange between the reactors, heat losses to surroundings and axial distribution of the MOx feed is used to study the performance of a 1.3 L system in terms of thermal efficiency and permeate flow rate. Efficiency and H₂ output are favored by higher flow rates, which result in higher temperatures. Combustion of recycled effluent produces hot spots, but distributing the feed axially mitigates the non-uniformity, and improves efficiency and permeate flow rate. Some distinct dynamical aspects are presented. We conclude that such a nonadiabatic autothermal system can operate at efficiencies of ∼66% and expected power density of 0.5 kW/L at maximum MSR temperature of 700 °C, when feeding the MSR reactor with liquid H₂O instead of pre-vaporizing it. This represents significant improvement over previous designs, and is currently tested experimentally.

Original language	English
Pages (from-to)	123-136
Number of pages	14
Journal	Chemical Engineering Journal
Volume	282
DOIs	https://doi.org/10.1016/j.cej.2015.02.031
State	Published - 15 Dec 2015
Externally published	Yes

Keywords

Autothermal reforming
Exothermic and endothermic reactions coupling
Hydrogen production
Membrane reactors
Modeling
Process integration

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.cej.2015.02.031

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title = "Design concepts of a scaled-down autothermal membrane reformer for on board hydrogen production",

abstract = "The design of an on-board autothermal membrane reactor producing pure hydrogen at atmospheric pressure, while recuperating heat, is analyzed mathematically. The suggested design incorporates two reactors exchanging heat; an endothermic methane steam-reforming (MSR) reactor embedding Pd membranes to separate pure H2, and an exothermic methane oxidation (MOx) reactor fed by the MSR effluent. The analysis is conducted at three levels of details: (i) Thermodynamics reveals that the minimum operating temperature for high thermal efficiency under adiabatic conditions with full recycle of MSR effluents is 550 °C. Feeding the oxidation reactor with added fuel does not improve efficiency. (ii) A kinetic model that accounts for the permeance of the Pd membranes suggests even higher temperatures should be considered when operating with limited membrane area. The effect of catalytic kinetics is small. (iii) A transient detailed one-dimensional model considering heat exchange between the reactors, heat losses to surroundings and axial distribution of the MOx feed is used to study the performance of a 1.3 L system in terms of thermal efficiency and permeate flow rate. Efficiency and H2 output are favored by higher flow rates, which result in higher temperatures. Combustion of recycled effluent produces hot spots, but distributing the feed axially mitigates the non-uniformity, and improves efficiency and permeate flow rate. Some distinct dynamical aspects are presented. We conclude that such a nonadiabatic autothermal system can operate at efficiencies of ∼66% and expected power density of 0.5 kW/L at maximum MSR temperature of 700 °C, when feeding the MSR reactor with liquid H2O instead of pre-vaporizing it. This represents significant improvement over previous designs, and is currently tested experimentally.",

keywords = "Autothermal reforming, Exothermic and endothermic reactions coupling, Hydrogen production, Membrane reactors, Modeling, Process integration",

author = "Michael Patrascu and Moshe Sheintuch",

note = "Publisher Copyright: {\textcopyright} 2015 Elsevier B.V.",

year = "2015",

month = dec,

day = "15",

doi = "10.1016/j.cej.2015.02.031",

language = "英语",

volume = "282",

pages = "123--136",

journal = "Chemical Engineering Journal",

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publisher = "Elsevier",

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TY - JOUR

T1 - Design concepts of a scaled-down autothermal membrane reformer for on board hydrogen production

AU - Patrascu, Michael

AU - Sheintuch, Moshe

PY - 2015/12/15

Y1 - 2015/12/15

N2 - The design of an on-board autothermal membrane reactor producing pure hydrogen at atmospheric pressure, while recuperating heat, is analyzed mathematically. The suggested design incorporates two reactors exchanging heat; an endothermic methane steam-reforming (MSR) reactor embedding Pd membranes to separate pure H2, and an exothermic methane oxidation (MOx) reactor fed by the MSR effluent. The analysis is conducted at three levels of details: (i) Thermodynamics reveals that the minimum operating temperature for high thermal efficiency under adiabatic conditions with full recycle of MSR effluents is 550 °C. Feeding the oxidation reactor with added fuel does not improve efficiency. (ii) A kinetic model that accounts for the permeance of the Pd membranes suggests even higher temperatures should be considered when operating with limited membrane area. The effect of catalytic kinetics is small. (iii) A transient detailed one-dimensional model considering heat exchange between the reactors, heat losses to surroundings and axial distribution of the MOx feed is used to study the performance of a 1.3 L system in terms of thermal efficiency and permeate flow rate. Efficiency and H2 output are favored by higher flow rates, which result in higher temperatures. Combustion of recycled effluent produces hot spots, but distributing the feed axially mitigates the non-uniformity, and improves efficiency and permeate flow rate. Some distinct dynamical aspects are presented. We conclude that such a nonadiabatic autothermal system can operate at efficiencies of ∼66% and expected power density of 0.5 kW/L at maximum MSR temperature of 700 °C, when feeding the MSR reactor with liquid H2O instead of pre-vaporizing it. This represents significant improvement over previous designs, and is currently tested experimentally.

AB - The design of an on-board autothermal membrane reactor producing pure hydrogen at atmospheric pressure, while recuperating heat, is analyzed mathematically. The suggested design incorporates two reactors exchanging heat; an endothermic methane steam-reforming (MSR) reactor embedding Pd membranes to separate pure H2, and an exothermic methane oxidation (MOx) reactor fed by the MSR effluent. The analysis is conducted at three levels of details: (i) Thermodynamics reveals that the minimum operating temperature for high thermal efficiency under adiabatic conditions with full recycle of MSR effluents is 550 °C. Feeding the oxidation reactor with added fuel does not improve efficiency. (ii) A kinetic model that accounts for the permeance of the Pd membranes suggests even higher temperatures should be considered when operating with limited membrane area. The effect of catalytic kinetics is small. (iii) A transient detailed one-dimensional model considering heat exchange between the reactors, heat losses to surroundings and axial distribution of the MOx feed is used to study the performance of a 1.3 L system in terms of thermal efficiency and permeate flow rate. Efficiency and H2 output are favored by higher flow rates, which result in higher temperatures. Combustion of recycled effluent produces hot spots, but distributing the feed axially mitigates the non-uniformity, and improves efficiency and permeate flow rate. Some distinct dynamical aspects are presented. We conclude that such a nonadiabatic autothermal system can operate at efficiencies of ∼66% and expected power density of 0.5 kW/L at maximum MSR temperature of 700 °C, when feeding the MSR reactor with liquid H2O instead of pre-vaporizing it. This represents significant improvement over previous designs, and is currently tested experimentally.

KW - Autothermal reforming

KW - Exothermic and endothermic reactions coupling

KW - Hydrogen production

KW - Membrane reactors

KW - Modeling

KW - Process integration

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U2 - 10.1016/j.cej.2015.02.031

DO - 10.1016/j.cej.2015.02.031

M3 - 文章

AN - SCOPUS:84947868080

SN - 1385-8947

VL - 282

SP - 123

EP - 136

JO - Chemical Engineering Journal

JF - Chemical Engineering Journal

ER -

Design concepts of a scaled-down autothermal membrane reformer for on board hydrogen production

Abstract

Keywords

UN SDGs

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